Electric oil pump control system and control method for automatic transmission

Abstract

A control method of an electric oil pump for an automatic transmission that minimizes power loss by normally controlling driving of the electric oil pump when a start intention of a driver is detected after a power source is turned on is provided. The method includes driving an electric oil pump at ‘A’ RPM which is a maximum velocity when the power source is turned on. The driving of the electric oil pump is stopped when a set time t determined by the temperature of the automatic transmission oil has elapsed. The electric oil pump is driven at ‘A’ RPM for the time t, and thereafter, the electric oil pump is driven at ‘B’ RPM when a selection of a driving shift stage is detected.

What is claimed is: 
     
       1. An electric oil pump control system for an automatic transmission, comprising:
 a power source comprising an engine or a motor; 
 an electric oil pump supplying a fluid to the automatic transmission; 
 an information detector detecting information on driving of a vehicle; and 
 a controller controlling operations of the power source, the electric oil pump, and the automatic transmission based on the driving information of the vehicle, 
 wherein the controller drives the electric oil pump when a start intention is detected after the power source is turned on, and 
 wherein the controller feedback-detects a velocity of the electric oil pump while driving the electric oil pump at a first revolutions per minute (RPM) and stores a trouble code and outputs a trouble message when the driving of the electric oil pump does not follow a control command. 
 
     
     
       2. The system of  claim 1 , wherein:
 the information detector detects the driving information including a turn-on/off request of the power source, a driving shift stage selected by a shift lever, a temperature of the automatic transmission oil, an input torque of the automatic transmission, an input RPM of the automatic transmission, a velocity of the electric oil pump, and a pedal effort of a brake pedal. 
 
     
     
       3. The system of  claim 1 , wherein:
 the controller determines whether there is the start intention when a driving shift stage is selected after the power source is turned on to drive the electric oil pump. 
 
     
     
       4. The system of  claim 1 , wherein:
 the controller drives the electric oil pump at the first RPM which is a maximum velocity for a set time in order to supply sufficient oil to a hydraulic line of the automatic transmission when the power source is turned on. 
 
     
     
       5. The system of  claim 4 , wherein:
 the time t, when the electric oil pump is driven at the first RPM, is determined depending on an oil temperature of the automatic transmission. 
 
     
     
       6. The system of  claim 3 , wherein:
 the controller drives the electric oil pump for a set time at the first RPM, and thereafter, drives the electric oil pump at a second RPM when the driving shift stage is selected by a shift lever. 
 
     
     
       7. The system of  claim 6 , wherein:
 the controller determines the second RPM of the electric oil pump according to conditions of an oil temperature of the automatic transmission, an input torque input into the automatic transmission, an RPM inputted into the automatic transmission, and a velocity of the electric oil pump. 
 
     
     
       8. A control method for an automatic transmission, comprising:
 firstly driving an electric oil pump at a first RPM which is a maximum velocity when a power source is turned on; 
 stopping the driving of the electric oil pump when a set period of time, which is determined by a temperature of an automatic transmission oil, has elapsed; and 
 secondly driving the electric oil pump at the first RPM for the set period of time; and 
 driving the electric oil pump at a second RPM when selection of a driving shift stage is detected, 
 wherein, during the firstly driving of the electric oil pump at the first RPM, a trouble code is stored and a trouble message is output when the electric oil pump does not follow a control command. 
 
     
     
       9. The method of  claim 8 , wherein:
 the second RPM is determined according the temperature of the automatic transmission oil, an input torque input into the automatic transmission, an RPM inputted into the automatic transmission, and a velocity of the electric oil pump. 
 
     
     
       10. The method of  claim 8 , wherein:
 the secondly driving the electric oil pump at the first RPM assures start responsiveness just after the driving shift stage is selected.